For music services such as Spotify and Rhapsody, perhaps the biggest threat is coming from artists themselves, and a practice some are calling "windowing." Are staggered releases a staggeringly bad idea?

The music industry may soon be acting even more like the film business and delaying streaming songs to avoid cannibalizing sales."Windowing," says Jon Irwin, CEO of subscription-based music streaming service Rhapsody, "[is] fundamentally the wrong thing to do."